가용 수자원 지수를 이용한 한국과 전 지구 수자원의 분포와 변동성

Abstract

This study verified that it is possible to classify water resources climate by precipitation using available water resources index (AWRI). To investigate water resources climate quantitatively, water resources indicators (WRI) has been made, which directly indicate seasonal and regional concentration, annual deviation, and maximum variability of water resources. Using WRI, water resources climate of both South Korea and global region was diagnosed quantitatively. WRI is consisted of annual precipitation average and primary statistics of AWRI. AWRI is the accumulated precipitation value in which daily reduction of water, and the duration of accumulation are taken into account quantitatively. Firstly, the representativeness of water resources is verified through the comparison between AWRI and water level of 10 Dams of 4 main rivers in South Korea. The result appears positive correlation increasing logarithmically (R: 0.53~0.74, R2: 0.30~0.57). Also, the pattern of daily water level between observation and calculation using estimated regression equation shows similar trend (R: 0.81, R2: 0.66, RMSE: 4.69 m) in Soyang river Dam during Jan 01~Aug 21, 2011. Secondly, because water resource index has a certain value although daily precipitation is zero, it is possible to analyze the characteristics of water climate not to be calculated by precipitation data due to disorder of its occurrence and intensity. In analysis of rotated empirical orthogonal function (REOF), annual variability between precipitation and AWRI coincided with the spatial pattern of REOF1-5, respectively. However, monthly variability has a different spatial pattern of the first EOF1, as precipitation (AWRI) appeared a principal variability at Seoul and Kyeonggi province (Southern coastal area and Jeju Island). All of REOF2-5 shows a different spatial distribution. In analysis of daily variability between daily precipitation and daily AWRI at Seoul in 2010, daily precipitation has many days with zero value, and its occurrence and intensity are disorder, it is difficult to represent plentiful water resources (annual precipitation of 2010: 2,033mm, annual normal precipitation: 1,345mm), but AWRI is very good indicator to indicate the date and water resources anomaly to normal (positive AWRI anomaly from 236 Julian day) of Seoul in 2010. In a periodicity analysis using Fourier Transform, both precipitation and AWRI has 365days period with the largest amplitude. Except for 365days, precipitation showed strong amplitude at short periods (182.5, 60.8 days); AWRI did at long periods (6.0, 4.3 years). Thirdly, the results applied WRI with South Korea (19881-2010): Sungsan station of Jeju Island has the most abundant annual mean precipitation (1,930 mm) and daily mean water resources (298 mm), however Daegwallyeong station has the largest difference of water resources variability (591 mm). Also, the mean occurrence date of annual water resources maximum (minimum) is the fastest at Gunsan with 216 Julian day (Gangneung with 258 Julian day) station, is the latest at Seogwipo with 96 Julian day (Ulleungdo with 183 Julian day) station. South Korea is classified with 5 sub-regions (group 1: mid-western region, group 2: eastern costal region, group 3: southeastern costal region, group 4: southwestern costal region and Jeju Island, and group 5: Seoul, Kyeonggi province, a part of kwangwon province, and Ulleungdo) by K-mean cluster analysis using annual AWRI anomaly. Group 3 and 4 have an abundant precipitation and water resources however, the largest difference of water resources variability appear at group 3, 4, and 5. The different tempo-spatial distribution of water resources between middle and southern region of South Korea is verified at water resources map using daily mean AWRI. In case of Seoul with precipitation data of more than 200years (1777-2010), the difference of AWRI variability has the increasing trend with 29.7 mm/100 years as increasing ratio of annual AWRI maximum (45.7 mm/100 years) is larger than one of annual AWRI minimum (16.9 mm/100 years). The distribution of water resources in global region (1981-2008) using CMAP pentad precipitation was investigated with WRI. The results are that equator region has an abundant water resources however, the difference of water resources variability is the highest in area of 10~20？N of both hemispheres. South Korea and southern region of Japan were verified to have a large difference of water resources variability, although they are located in middle latitude of northern hemisphere. Also, AWRI peak was occurred 10 pentads after precipitation peak in region with much precipitation, on average, calculated by lag-correlation coefficients. However, the region has smaller precipitation, the lag-correlation coefficient is smaller. In addition, relation between AWRI and ENSO index was investigated during 1981-2008. Water resources have characteristics with locally differences over global region. The largest positive AWRI anomaly appeared at Borneo Island located at Southeastern Asia in El Ni？o years (7 years: 1982, 1986, 1987, 1991, 1997, 2002, and 2006). These results could be compared with precipitation. Negative AWRI anomaly appeared at South Korea in La Ni？a years (4 years: 1988, 1998, 1999, and 2007) however, no effect in El Ni？o years.